1. Field of the Invention
The present invention relates to a catch device of a cockpit door disposed between a cockpit and a passenger cabin on an aircraft.
2. Description of the Related Art
Devices for locking a door using solenoid are disclosed in the following patent documents: Japanese Patent Application Laid-Open Publication No. 2003-113684 (patent document 1); Japanese Patent Application Laid-Open Publication No. 2003-74232 (patent document 2); and Japanese Patent Application Laid-Open Publication No. 2000-35656 (patent document 3).
The cockpit door is a single swinging hinged door equipped with a mechanism for locking and unlocking the door using a latch and a catch disposed on the side of the door opposite from the hinge.
The cockpit door has a latch provided on the cockpit side for safety. According to a known system, the catch is designed to be retained by a solenoid, and an electric switch provided on the passenger cabin side is used for releasing the catch.
In such system, the electric switch provided on the passenger cabin side can be, for example, a numeric keypad switch, which is operated by inputting a security code number.
The system is designed so that the solenoid retains the catch when power is supplied thereto. One reason for this is because the system is designed so as not to obstruct maintenance crews from entering the cockpit, for example, when the aircraft is subjected to maintenance on the ground.
However, if power to the solenoid is shut down by some reason during flight of the aircraft, the catch of the door will be released and the cockpit door may unexpectedly be opened.